Recently, semiconductor light-emitting devices have been studied for application to displays or to lighting instruments. The semiconductor light-emitting device generally includes electrodes and a semiconductor layer placed between them, and emits luminescence when current flows between the electrodes. Normally, the device has a pad electrode in ohmic contact with the semiconductor layer, and the luminescence is given off from the periphery of the pad electrode when the current flows. If used as a lighting instrument, the light-emitting device is preferred to be relatively large. However, enlarging the pad electrode is not effective in expanding the light-emitting part, and hence, practically a thin wire electrode is additionally put from the pad electrode along the semiconductor layer surface so that the light-emitting part can be expanded. On the other hand, if the thin wire electrode is extended, it generally causes a problem of making the electrode structure complicated.
From the viewpoint of application to lighting instruments, it can be also considered to supply an enough amount of current for the devices to enhance the luminance intensity. In a conventional semiconductor light-emitting device including the pad electrode, the luminance intensity increases according as the current increases until a certain value but then the intensity reaches the peak at the certain current value. Even if the current increases more than that value, the luminance intensity does not increase but decreases. A big reason of this is because large current flows in the device to generate too much heat to cool sufficiently. Accordingly, in order to enhance the luminance intensity of a conventional device, it is preferred to cool the device sufficiently. To cope with this problem, it is proposed to provide a heat-sinking substrate on the bottom of the device. However, that is not very effective at present because the substrate is positioned too far from the heated part.